Can closure and method of making the same



May' 30, 1944 r A. e. HATCH 2,350,312 7 CAN CLOSURE AND METHOD OF MAKINGTHE SAME I Filed Feb. 1o, 1945 2 Sheets-Sheet 1 May 30, 1944. I 'A. G.HATCH 2,350,312

CAN CLOSURE AND METHOD OF MAKING THE SAME Filed Feb. 10, 1943 2Sheets-Sheet 2 Eg -5 a 1 J INVENTOR." I flzez'aizderdfiaztia W *MMJwiiiorzae ys Patented May 30, 1944 THE SAM

Alexander Hatch, ltutland, Vt., assignor to ry Corporation, Rutland,

Fibre Can Machine Vt., a'corporation Application February 10, 1943,Serial No. 475,351

1 Claim. ('Cl. 229-55) The present invention relatesto closures for cansutilized for the packaging of motor oils and the like, and, moreparticularly, to top closures for fibre bodied containers intended forthe purposes mentioned. The invention also relates to" the method ofmaking the closures and applying the same to the can bodies.

It is recognized that closures forme of fibrous material for closing thebottoms of container bodies have been proposed which are generally"satisfactory, but' so far as I am aware, no satisfactory closure hasbeen provided whichmay be used to cover and seal the top of thecontainer after the same has been filled with a liquid.'

Many efiorts over a long period of years have been made in an endeavorto provide a satisfactory top closure which meets necessaryrequirements, but so far as the practical art is developed, no suchclosure, prior to the present invention, has been produced.

Therefore, an aim of the present invention is to provide an improved andnovel closure having various features of novelty and advantage and whichis peculiarly adapted for use for closing the top of the container afterthe container has been filled with a liquid or the like.

A further object of the invention is to provide very simple, economical,and effective closures which may be cheaply manufactured and sold ascomplete unitary structures and which may be very quickly and readilyassembled on the can bodies and particularly on the tops of the canbodies after they have been filled with oils or'the like.

A further object of the invention is to provide a closure which is verystrong and sturdy; which will withstand hard usage, and which is capableof effectively resisting blows and shocks exerted thereon when the canis roughly handled or dropped. In fact, a closure constructed inaccord'ance with the present invention, when applied to a can body, iscapable, although the closure comprises a body member offibrous'material, of better withstanding shocks and blows than are metalclosures such as are usually employed on containers of this sort.

.j 'A further aim of the invention is to provide a closure which willprovide an eflective liquid-tight and leak-proof joint between theclosure and the end of the can body to which the closure is applied.Further, th arrangement is such that the liquid contents of .thecontainer cannot gain access to the end of th fibre can body, with theresult that wicking is prevented, that is, the liquid cannot gain accessto the raw edge of the can body and then permeate through the wallthereof. A still further object of the invention is to provide a closureof simplified construction and one which may be inexpensivelymanufactured, it being possible with my improved arrangement to make theclosure out of inexpensive materials and to produce the closures at highrates of speed -so that they can be produced at a relatively low cost,the said closures so produced being in the form of self-contained unitsor structures which are ready for application to the can bodies andparticularly to the'tops thereof after the. same have been'filled withoils or the like. 7

A further object of the invention is to provide animproved andsimplified method formanufacturing my improved closures and applying thesame to the ends of a can body and particularly the top thereof.

Other objects will be in. part obvious and in part pointed out more indetail hereinafter.

In the accompanying drawings: Figure 1 is a side elevational view of oneembodiment of my improved closure with portions thereof in centraltransverse section;

- Fig. 2 is a view similar to Fig. 1 but showing the improved closurethereof assembled on a can 'proved closure comprises a body member toformed of fibrous material, such as. inexpensive strawboard, and havinga disk portion II and a peripheral flange ii. The disk portion ispreferably inwardly eoncaved or dished slightly in order that it mayhave somewhat'of a bellows action and thus permit the closure to morereadily acconimodate pressures which may be set up within the can ofwhich the closure forms a part. The

.margin of the disk portion ll may bev inclined upwardly and outwardlyas at l3 so as to provide a conical portion which terminates in theflange l2. Thus, at the juncture of the disk portion and v the flange,an internal annular channel is provided, one wall of which is formed bythe flange l2 and the other wall of which is formed by the tapered orconical portion l3 of the disk.

' The closure further includes an oilproof membrane entirely coveringthe inside of the bodymember in including the inner surface of the toform a sealing bead between the end of the.

can body and the closure when the closure is heat-sealed to the canbody.

In the embodiment of the: invention shown in Figs. 1 and i, the membraneconstitutes a coating ll of an oil-proof, film-forming, thermoplasticadhesive which covers the exposed inside surface of the flange i2 andthe bottom surface of the disk portion ll of the body member IO, andthis coating is of substantially increased thickness at the juncture ofthe flange and the disk portions so as to provide an annular ring Hwhich, as hereinafter described, forms a sealing 90 and corresponds inshape to, the body member.

bead or fillet between the closure and the end of the can body on whichit is assembled.

The improved closure shown in Figs. 1 and 2 may be very economically andreadily manufactured by passing a strip of fibrous material (herelnreferred to as cap stock) through a cap press of conventional designwhereby blanks are cut out from the strip and drawn to the shapeillustrated in Fig. l of the drawings. ,After the body members are thusformed, a quantity of oilproof, thermoplastic, film-forming adhesive isapplied to the entire inner surface of the body member and in suchmanner that an annnular ring or gasket i4 is formed at the juncture ofthe flange and the disk portion. This may be done by depositing ameasured amount of thermoplastic material onto the disk at the centerthereof and rapidly rotating the closure so as to cause thethermoplastic material, due to centrifugal force, to flowoutwardly ofthe disk and up along the flange. when rotation ceases, the excessmaterial will collect at the juncture of the flange and disk portion andform the annular ring or gasket l4. The'thermoplestic coating ispermitted to cool and harden. The closures are now complete and may behandled and shipped as unitary structures ready to be applied to the canbodies at the point at which the containers are filled.

In Fig. 2, the closure of Fig. 1 is shown as having been applied to acan body 25 which may be of any suitable construction but which is hereshown as having a body portion of suitable fibrous material, such asinexpensive chipbou'd, which may be wound into a plurality of plies toprovide the desired strength and bulk. The can body is shown as having alining 26 which may com- 55 prise a sheet of oil impervious materialadhesively secured to the inner surface of the body portion of the can.In application, the closure is slipped over the upper end of the canbody heat-sealed thereon by means of a heated pressure ring whichcontracts the flange of the closure against the outside surface of thecan body and at the same time applies heat to the flange. Thethermoplastic coating, together with the annular ring it thereof, isrendered viscous and tacky and, during the sealing operation, theclosure and can body are urged axially towards one another with theresult that the end edge of the can body becomes embedded in the annularring ll of the thermoplastic material and causes the excessthermoplastic material thereof to form a "fillet or gasket in the cornerbetween the inside surface of the can body at one end thereof and.

margin. of the disk. When cooled, the thermoplastic coating. forms avery tight and secure I bond between the flange of the closure and thecan body, and the fillet forms an eflective seal 5 which prevents thecontents of the can from seeping up along the inside surface of the canto the raw edge of the can body. This fillet tapers down and spreads outalong the inside wall of the can body and inwardly of the disk portionof the body member l0.

13 of being constituted of only the thermoplastic coating I4, also.comprises a lining i6 of a thin flexible oilproof sheet material, suchas Cellophane. In each of the embodiments of Figs. 3 and 4, the liningis preferably coextensive with,

It fits within the body member. By preference, there is provided betweenthe opposed surfaces of the flanges of the lining member and the bodymember a film ll of adhesive material, and this adhesive material, inthe event that it is desired to permanently secure theflanges of thelining and the body member, is preferably of a thermoplastic nature and,sufficient quantity to serve the purpose stated but, in the event thatit is 80 desired to provide a closure, the body member of which may beeasily removed from the linin after the closure has been applied to thecan body, the adhesive may be of such nature or of such small amount asto secure the flanges to- 85 gether only to the extent that the partswill not separate during handling and will permit the body member to beeasily removed from the lining without disturbing the relation of thelining to the can body. In the drawings, the film or layer H of adhesivematerial is shown as being interposed between the disk portions of thebody member and the lining as well as the flanges thereof; Bypreference, and for a purpose later described, the disk portion of thelining is not adhesively secured to the disk portion of the body acterof, and applied in a manner similar to, the

coating of the flrstembodiment. This coating is of thermoplastic,film-forming adhesive and covers the exposed surface'of the flange ofthe lining and extends onto the disk portion thereof,

tially increased thickness at the juncture of the flange and diskportions of the lining so as to provide the annular ring N. In Fig. 4,the coating of thermoplastic, film-forming adhesive cov- (which mayfirst befilled with liquid) and is then erg t ti tt surface of t diskportion of the lining so that the lining is rendered tougher andstronger throughout. However, where it is desirable to save expense inthe amount of the thermoplastic adhesive employed, the coating,

may extend only partially onto the disk portion of the lining, thecentral portion of the disk being free of suchcoating, as shown in Fig.8. v

The improved closures, shown in Figs. 3 and 4.

may be very economically and readily manufactured by proceeding inaccordance with the following preferred method: A strip of fibrousmaterial, herein referred to as cap stock, and from which the bodymembers are to be formed, may be first coated with a thin layer ofthermoplastic the inside swam the My member at the adhesive and, afterthe adhesive has thoroughly the coating in each instance being ofsubsten- 'iorming to the shape of the recess.

dried, a sheet of thin oilprooi sheet material; such as Cellophane, islaid on top of the cap stock with the adhesive coating between the twosheets. Of course, if desired, the thin layer of thermoplastic adhesivemay be applied to one sideof the Cellophane lining instead of the stockmaterial. The superimposed layers are then run throtlgh a cap press ofconventional design. This press may have a female die provided with arecess corresponding in shape and size to the external shape of theclosure to be formed, and a male die con- As the die members are broughttogether, they cut from the superimposed layers a-blank and draw theblank to the shape illustrated. During the cap drawing operation, heatis generated due to friction at 'the flange forming portions of the diemembers so that the adhesive between the flanges of the body member andlining is rendered yiscons and tacky with the resultthat it will adhereto both of the opposed surfaces of the flanges. Then, when the capis-ejected from the female die, the adhesive is allowed to cool andharden so that the flanges of the body portion and lining are adhesivelysecured together sufliciently to keep the Cellophane and body membertogether until the cap is used. During the operation of drawing theclosure to form, there is. not .suflicient heat generated .to render theadhesive l1 between the disk portions of the body member and the liningtacky so that in the finished closure the disk portions will not beadhesively securedtogether, that is, they are substantially loose of oneanother, as indicated by the space shown in Fig, i therebetween. Afterthe closures are thus formed, a quantity of an oilproof thermoplasticfilm-forming adhesive is applied to the lining to form thecoatingll'with the annular ring or gasket ll at the juncture of theflange and the disk portion of the lining. This may bev done bydepositing ameasured amount of thermoplasticmaterial on the disk portionand theri rotating the closure, as described in connection with theembodiment shown in Fig. 1. In case it is not desired to cover theentire disk portion of the lining, asshown in Fig. 3, the measuredamount of thermoplastic material is deposited onto the disk portion ofthe lining at a point oil center thereof. The thermoplastic coating ispermitted to set. The closures are now unitary structures ready to beapplied. V

The closures shown in Figs. 3 and 4 are applied to the end of the canbody in a manner similar to that described in connection with the firstembodiment of the invention. The cap is slipped over the end of the canbody and is then heatsealed thereon by means of apressure ring. soheat-sealing the ring, if the adhesive layer H between the flanges ofthebody member and the lining i6 is of a thermoplastic nature and issumcient in quantity, it is rendered viscous and tacky so that a strongbond is obtained therebetween after cooling. Further, during suchheat-seal: ing, the closure is moved downwardly over the from seeping upalong the side of the inside of the can to the raw edge of the can body.

From the foregoing description taken in connection with the accompanyingdrawings, it will be seen that in each embodiment of the invention Iprovide a very simple and effective can closure which may bemanufactured of relatively cheap materials and which may be economicallymade at a high rate of production. The closures may be handled andshipped as complete structures ready to be applied to the cans at thefactories or places at which the cans are filled. Furthermore, the capsmay be very quickly and readily applied to the can bodies after thelatter are filled and,.when so applied, ail'ord very effective, strongand sturdy closures. In each instance, the closure has on its under facea membrane coextensive therewith, and the membrane is of an oilproofcharacter so as to render the body portion of the closure impervious tooil. Furthermore, in each instance, the thermoplastic gasket at thecorner between the disk portion of the can and the inside wall of thecan body forms an effective seal which prevents seepage or leakage. Thisgasket further. has the advantage in that it is resilient and yet toughand, therefore, will absorb shocks and strains exerted on the corher ofthe closure and thus aid in preventing top edge of the can body, so asto embed that 1 edge into the annular ring H of the thermoplasticmaterial so that a fillet or gasketis formed between the inside surfaceof the can body at the secure bond between the flange of thelining l4and the can body, and the i'lllet forms an effective seal which preventsthe contents of the can rupture or breaking of the closure.

Where a lining I8 is providedfas shown in Figs. 3 and 4, the diskportions of the body member and, the lining of the closure are, aspreviously, stated, not securely bonded together, and the obat anylocality. Such sharp bending or creasing of the body member is almostbound tooccur from blows received during shipping or in carelesshandling of the filled cans. I have found from very extensive drop teststhat in cases where the disk portion of the lining is closely bonded tothe disk portion 'of the body member and the cap stock is severely orsharply bent (although it'is not ruptured), a microscopic rupture of thelining material frequently occurs which permits oil to leak through intocontact with the cap stock, thus causing wicking. This does not occurwhere the disk portion of the lining is relatively free of the capstock. I have further .found from these drop tests that the canmay bedropped many, times without completely rupturing the cap stock but uponfurther dropping of the can a point is reached where the cap stock isactually ruptured but, even in these instances, the lining has not beenadversely affected or ruptured and the effective seal still remains sothat the contents of the can cannot leak or seep out.

As many changes could be made in the aboveconstruction and manyapparently widely .different embodiments of this invention could be madewithoutdeparting from the scope thereof,

used in the following claim is intended to cover all of the generic andspecific teaturesiot the invention herein'describedand all statements ofthe scope of they invention which, as a matter of language, might besaid to fall therebetween.

I claim as my invention: A closure for closing flbrous' container bodiesfor the packaging of oil or the like, said closure comprising a bodymember having ,a disc for 5 covering the top of the container and aperipheral flange adapted to engage the exterior of a container body,said disc being depressed inwardly to provide a central portion and acircumferential channel between the flange and central portion, acoating oi normally non-viscous thermoplastic adhesive material on theinner face of the flange and the disc, said coating in the channel beingof increased thickness to substantially fill the channel, said materialbeing of the type which becomes viscous and tacky upon application ofheat to provide a resilient sealing bead in the comer between the innersurface of a container body and the inner face of the disc of theclosure when the closure isheat sealed to a conlQ tainer body.

ALEXANDER G. HATCH.

